TM 10-3930-669-20 WARNING Remove  all  jewelry  such  as  rings,  dog  tags,  bracelets,  etc.    If  jewelry  contacts  battery terminal,  a  direct  short  may  result  in  instant  heating  of  tools,  damage  to  equipment,  and injury or death to personnel. VOLTAGE TEST (1) Set    multimeter    select    switch    to VOLTS DC. (2) Connect     positive     (+)     multimeter lead to relay R4, terminal 30 cavity. (3) Connect    negative    (-)    multimeter lead to a known good ground. (4) Set   MAIN   POWER   switch   to   ON position (TM 10-3930-669-10). (a) If  there  are  not  22  to  24  vdc present, perform Step (5) below  and  repair  wire  7  (see schematic Appendix F). (b) If    there    are    22    to    24    vdc present, wire 7 is OK. (5) Set  MAIN  POWER  switch  to  OFF position. CONTINUITY TEST (1) Set    multimeter    select    switch    to OHMS. (2) Check  continuity  between  relay  R4, terminal   87   cavity   and   connector P10, terminal 3. (a) If  there  is  no  continuity,  repair wire 9A (see schematic Appendix F). (b) If   there   is   continuity,   replace relay R4 (Para 7-33). (3) Install relay R4. 2-55